But it isn't a great idea to jump on climbs after six weeks of total layoff. You've got to bring these injuries back gradually, otherwise they have a way of springing Phoenix-like from the ashes of indolence and picking up exactly where they left off weeks ago when you stopped climbing. I've seen friends go through multiple cycles of rest and reinjury this way.

I've rehabbed some nasty pulls with a hangboard. But it has to be mounted so that you can grab the holds with your feet on the ground, thereby allowing you to get the injured hand in bona fide climbing positions but loaded with, at first, extremely low loads and always under complete control. You can walk your feet forward so that you are slightly overhanging to gradually increase the loads, but you are looking for levels of pulling that do not cause any pain. Try multiple sets of very light seven-second holds, never push past a pain barrier, and don't get hung up on doing better each time.

Eventually you can start picking your feet off the floor for sets of one-second hangs, finally building up to whatever training levels are normal for you.

In my totally inexpert opinion you've waited way too long to do this if you're planning on climbing in four days, but even a little light hand work will be better than nothing, and if the injury is still bad at least you'll know before you get in a position on a climb that forces you to pull hard regardless of how ready your hand is.

I agree with Rich above, you need to start loading the injured tissue, in a gradual way. There are no formal protocols for how fast you should go. If you get a bit of discomfort while loading the tissue, that is OK, AS LONG AS the pain does not remain when you finish exercising.